1. Field of the Invention
The present invention relates to a centrifugal separator, and particularly to a rotor structure.
2. Description of the Related Art
In the centrifugal separator 100 diagramed in FIG. 9, a motor 101 is installed via elastic bodies 103 to flanges 102a formed inside a frame 102. To the drive shaft 104 of this motor 101, a rotor 105 is engaged so as to be freely removable.
In this centrifugal separator, the rotor 105 is formed in a disc shape. On the upper surface periphery of the rotor 105 is formed an inclined surface 105a that is inclined toward the inside and downward. In this inclined surface 105a, tube (test tube) insertion holes 106 are formed.
Now, a rotor 105 such as this is formed by machining an aluminum block or the like into a disc shape and then cutting the inclined surface 105a, using a lathe or the like, and thereafter making the tube insertion holes 106 with a drill or the like. Accordingly, the machining becomes intricate and costly. Also, with such a rotor 105 as this, a certain thickness is required in the peripheral portion of the rotor 105 for forming the tube insertion holes 106, resulting in increased weight. Accordingly, the motor 101 must have a sufficient capacity therefore, whereupon the centrifugal separator must be made large. In order to lighten the rotor 105, the center portion of the rotor 105 (the portion where the drive shaft 104 of the motor 101 is attached) and portions other than those portions needed for forming the tube insertion holes 106, indicated by the double-dotted lines in FIG. 9, can be cut away, but that results in the shape of the rotor 105 becoming complex and machining that is much more intricate. Furthermore, in order to accommodate other types of tubes having different diameters, other rotors 105 must be made available that are provided with tube insertion holes 106 having diameters corresponding to those other tubes, resulting in escalating costs.
In a centrifugal separator 110 diagramed in FIG. 10, a rotor 111 is configured by a main rotor body 112 provided with a plurality of holes 112a in the upper surface periphery of a disc, and cubical racks 113 loaded in the main rotor body 112. With this rotor 111, the main rotor body 112 is engaged to the drive shaft 104 of the motor 101, and the racks 113 are accommodated, respectively, in the holes 112a in that main rotor body
With such a rotor 111 as this, in order to prevent the weight from being displaced to one side, the multiple racks 113 must be accommodated respectively in the holes 112a of the main rotor body 112 symmetrically about the center of the drive shaft 104 to achieve balance. Since the operation of accommodating these racks 113 in the main rotor body 112 is intricate, and each of the racks 113 is formed independently, not all that many tube insertion holes (not shown) can be formed in the upper surface of the racks 113.
Thereupon, an object of the present invention is to provide a centrifugal separator rotor that is both lightweight and easy to machine.
Another object of the present invention is to provide a centrifugal separator rotor wherewith the rack loading operation is simple, and the number of tube insertion holes can be increased.
Yet another object of the present invention is to provide a centrifugal separator rotor that can easily and inexpensively be made to accommodate various tube types.
In order to achieve the objects stated above, the centrifugal separator of the preset invention comprises: a cylindrical bottomed main rotor body; and a rack configured with a plurality of rack parts along the inner circumferential surface of the main rotor body, the rack parts of which are linked together and are able to move in radial directions of the main rotor body; wherein: when the main rotor body is being turned, the rack parts are pressed against the inner circumferential surface of the main rotor body and held there by the centrifugal forces associate with the turning of the main rotor body.
As based on the centrifugal separator of this invention, the rotor is made up of the main rotor body and the rack, respectively, as separate parts, wherefore the shape thereof can be simplified and machining made easy.
More specifically, because the main rotor body of the centrifugal separator of this invention can be a shape that stops the rack on the inner circumferential surface thereof, the main rotor body may have the simple structure of a bottomed cylinder, whereby the rotor can be made lighter in weight and less costly. It is also possible to form the rack of lightweight parts of plastic or the like, which not only facilitates cost reduction but also makes it possible to make the motor, etc., smaller, and thus to make the centrifugal separator both smaller and lighter in weight. Furthermore, when tubes are loaded into the rotor, the tubes can be loaded into a rack at another location beforehand and that rack then can be accommodated in the main rotor body. Thus, work efficiency is improved because only the lightweight rack need be moved, and tubes can be loaded into racks at other locations.
In a centrifugal separator of the present invention, moreover, a disc Is provided which fits tightly and integrally to the main rotor body at the center part thereof, and the multiple rack parts are linked together via the circumferential edge of the disc.
With the centrifugal separator of this invention, after mounting the rack parts about the circumferential edge of the disc, the disc is fit tightly on to the center part of the main rotor body. In this condition, when the main rotor body is driven so that it turns, the rack parts move out in radial directions due to centrifugal force, and are stopped when they come up against the inner circumferential surface of the main rotor body.
That is, with the centrifugal separator of this invention, the disc need only position the rack, and-need not have the strength required to hold the rack. Also, the rack is stopped by the inner circumferential surface of the main rotor body, due to the centrifugal force generated when the main rotor body is driven so that it turns, wherefore it is only necessary that the main rotor body retain sufficient strength, and thus the rotor can be made lighter.
In centrifuge operations, moreover, tubes are loaded into a rack at a different location beforehand, so that it is only necessary to mount the disc on which do racks have been mounted to the main rotor body. That is, only lightweight racks need be carried about, which makes the work easier.
In a centrifugal separator of the present invention, further more, a hub is erected in the center of the main rotor body. Splines are formed which extend upward and downward on the outer circumferential surface of the hub, and a spline hole is formed in the center of the disc. By pushing the spline hole of the disc down onto the splines of the main rotor body, the disc is made to fit tightly on the main rotor body.
With the centrifugal separator of this invention, the disc can be made to fit tightly to the main rotor body by pushing the center of the disc down onto the hub erected in the center of the main rotor body, wherefore the operation of mounting a rack on the main rotor body is extremely simple.
In a centrifugal separator of the present invention, moreover, grooves are formed in the inner circumferential surface of the rack parts. These grooves are made to mate with the circumferential edge of the disc, and, at the same time, the rack parts are mounted to the disc by pins inserted into the rack parts and the disc.
With the centrifugal separator of this invention, rack grooves are mated with the circumferential edge of the disc and the rack parts are held by the disc, wherefore the rack parts are securely held by the disc.
In a centrifugal separator of the present invention, furthermore, the rack is formed in a ring shape. At multiple locations in this rack, one slit is formed in a radial direction so as to completely cut and separate the rack, and slits are made in radial directions which cut the rack while leaving a portion of the inner circumferential edge thereof. The rack parts are formed by these slits so that they are divided.
As based on the centrifugal separator of this invention, the rotor is fabricated by a main rotor body and a rack, respectively, as separate parts, wherefore the shape is simplified and machining is made easy.
More specifically, the main rotor body need only be of a shape that will stop the rack with the inner circumferential surface thereof, wherefore the main rotor body can have the simple structure of a bottomed cylinder, and hence the rotor can be made lighter in weight and less costly. It is also possible to form the rack of lightweight parts made of plastic or the like, as a consequence costs can be reduced, the motor made smaller, and the centrifugal separator made both smaller and lighter in weight. Furthermore, when loading tubes into the rotor, the tubes can be loaded beforehand into a rack at a different location and then that rack accommodated in the main rotor body, so that it is only necessary to move the lightweight racks, making the work easier and enhancing work efficiency.
With the centrifugal separator of this invention, furthermore, the rack parts are formed integrally so that they do not separate, wherefore the number of tube insertion holes can be increased. In order to accommodate different types of tubes, moreover, it is only necessary to have racks that conform to the different tube types, using the same main rotor body in common, wherefore costs can be kept low.
In a centrifugal separator of the present invention, moreover, either projections or concavities are formed in the main rotor body while concavities or projections, respectively, are formed in the rack, so that the rack can be engaged with the main rotor body by those projections or concavities, such that the rack will be restricted to the same direction of turning as the main rotor body.
As based on the centrifugal separator of this invention, the engagement between the main rotor body and the rack can be implemented in a simple configuration, making it easy to mount the rack on the main rotor body.
In a centrifugal separator of the present invention, furthermore, the rack is configured with a ring-shaped main rack that is accommodated inside the main rotor body and auxiliary racks that accommodate pluralities of tubes, and auxiliary rack accommodation holes that are formed about the entire circumference of the main rack.
As based on the centrifugal separator of this invention, tubes are accommodated in tube-holding holes in the auxiliary racks, those racks are accommodated beforehand in the auxiliary rack accommodation holes in the main rack, and that [main rack] is accommodated inside the main rotor body. Accordingly, if auxiliary racks are provided which have tube-holding holes corresponding to different types of tubes, the main rack body and the main rack can be used commonly and costs reduced accordingly.
In a centrifugal separator of the present invention, moreover, projections or concavities are formed on the upper surface of one rack while concavities or projections, respectively, are formed in the lower surface of another rack, the other rack is mounted on the first rack, and the concavities or projections in the other rack in the upper stage are mated with the projections or concavities, respectively, in the first rack in the lower stage, thereby restricting the other rack in the upper stage to the same turning direction as the first rack in the lower stage.
With the centrifugal separator of this invention, the rack in the upper stage is restricted to the same circumferential direction as the rack in the lower stage by mating the concavities or projections in the rack in the upper stage with the projections or concavities, respectively, of the rack in the lower stage, thus making it possible to simultaneously centrifuge tubes accommodated in multiple stages of racks. This is very efficient, and makes it possible to simultaneously perform centrifuge operations on racks of different types, and, hence, on tubes of different types.